Hi Harini,
On Thu, Jul 10, 2014 at 11:31 AM, Harini Katakam
<harinikatakamlinux@xxxxxxxxx> wrote:
>>> + master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_RX_DUAL | SPI_RX_QUAD |
>>> + SPI_TX_DUAL | SPI_TX_QUAD;
>>
>> Your driver advertises Dual/Quad SPI Transfer capabilities, but it doesn't
>> check spi_transfer.[tr]x_nbits? How can it determine when to enable Dual/Quad?
>
> Here the driver is just giving information that the controller support it.
> The MTD layer enables dual/quad based on what the flash supports; quad
> being the first priority
> I understand that the spi core reads rx, tx-bus-width property and
> master support flags and
> performs the necessary checks.
That's correct: as long as the rx, tx-bus-width properties do not indicate a
Dual or Quad wiring, it won't be used.
However, based on schematics, someone may set the rx, tx-bus-width properties
to 4, which is correct, as DT describes the hardware. But this will fail to
work.
So I think it's safer not to announce Dual/Quad support in the driver until
the actual driver support is there.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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